JP3720417B2 - Magnet motor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an improvement in a small and simple magnet motor such as a fan motor.
[0002]
[Prior art]
Conventionally, brushless magnet motors, such as fan motors, where torque ripple is not a problem, use a single hall element with the same number of rotor magnets and stator tips or slots, and rotate them by energizing two coils alternately. I am letting. In this case, if a magnetic field symmetric with respect to the forward and reverse rotation directions is formed, a starting dead center is generated for the reason described later. Therefore, by providing a notch in a part of the tip, the magnetic pole of the magnet and the stator tip A method of avoiding dead points by deflecting the cogging torque generated during the period has become common.
[0003]
FIG. 2 shows a cross section of the magnetic circuit of such a conventional fan motor. In the figure, 1 is an annular rotor magnet with sinusoidal quadrupole magnetization, 1a is a zero-cross portion of magnetization, and 1b is a rotor yoke. Reference numeral 2 denotes a stator formed by laminating ten or more lamination cores punched from an isotropic silicon steel strip having four projecting teeth 2a, 2b, 2c, 2d, and bearing holes 2e. The stator 2 forms an outer rotor type magnetic circuit. The teeth 2a, 2b, 2c, and 2d have taps 2f, 2g, 2h, and 2i, respectively, and face the inner peripheral surface of the magnet 1, and the teeth 2b and 2d have their center angles indicated by chain lines 2bd.
Coils 3a, 3b, 3c, and 3d are wound around the outer periphery of each tooth, and 3a-3c and 3b-3d are respectively connected in series. An air gap 4 is formed between the inner periphery of the magnet 1 and the outer periphery of each tap, and a Hall sensor 5 is mounted on a non-display base plate in the gap between the tip 2f and the adjacent tap 2g.
[0004]
The tip 2f has a portion 2f1 protruding to the magnet side and a portion 2f2 retracted from the magnet, and the other tips 2g, 2h, and 2i are set in the same shape. Therefore, regarding the tip 2f, the magnetized center N of the opposing magnet 1 is attracted more strongly by the protruding side 2f1 of the tip 2f than the center line of the tooth 2a, and as a result, the position of the zero cross 1a moves to the position shown in the figure. Thus, the magnetic field is linked to the sensor 5. Accordingly, when an output voltage is generated in the sensor 5, this output voltage is signal-processed and applied to the drive circuit of FIG. 3A as an on / off signal. That is, a conduction signal is given to one of the bases of the semiconductor switches 6a and 6b constituting the power stage of the drive circuit, and one of the semiconductor switches 6a and 6b is closed, and the coil 31 or winding consisting of the windings 3a to 3c. An exciting current is supplied to the coil 32 made of 3b-3d, whereby a rotating magnetic force is generated between the magnet 1 and each tip, and the rotor rotates. Subsequently, when the output voltage of the sensor alternates due to the rotation of the rotor magnet, both switches open and close alternately, and the rotation of the rotor continues.
[0005]
By the way, in the magnetic circuit of FIG. 2, if there is no deformation such as the overhanging portion 2f1 and the retreating portion 2f2 on the tip, the magnetic pole center of the magnet only attracts the center line of each tooth. At this time, since the zero cross 1a is located on the center line of the gap portion between the tips, the magnetic flux is not interlinked with the sensor 5, and the energization cannot be obtained. Depending on the drive circuit, there is one that is automatically energized when a signal does not arrive for a certain period of time, but even if energization is obtained, the radial relationship between the magnet and the tip is such a positional relationship. It only pulls in or repels the direction and does not start the rotor. Therefore, in the conventional magnetic circuit, it is indispensable to deviate the rotor magnet with respect to the circumferential direction by notching the shape of each tip outer periphery facing the inner periphery of the magnet 1.
[0006]
Here, the relative position between the tip and the rotor magnet at the time of non-energization will be described in detail as follows. In general, in a magnetic circuit (four poles and four slots) in which the number of magnetic poles and tips is 4, assuming that the shape of the tip is a symmetrical shape without notches as shown in FIG. A stable point or starting dead center is encountered. Of these, 4 are unstable temporary dead points, 4 are stable true dead points, and the case where the above-described magnet magnetic pole and tip are attracted corresponds to a true starting dead point. In this case, the angle between adjacent true dead points is 90 °, the angle formed by the true dead center with respect to the center angle of the teeth is 45 °, and the teeth center angle is the center of the adjacent dead center angle. Located in.
However, if the stator is a notched tip as shown in FIG. 2, the angle between the true dead points is still 90 °, but the angle between the center angle of the teeth and the dead point is relative to the circumferential direction. For example, the bias is 20 ° to 70 °, and as a result, the starting dead center is eliminated.
[0007]
Regarding the reason why the rotor is deviated by the notch of the tip, in the case of FIG. 2, the radial length of the gap 4 formed facing the inner circumference of the rotor magnet 1 is asymmetric with respect to the rotational direction. The magnetic resistance of the air gap and hence its attractive force is also asymmetric. Therefore, the magnetic poles of the rotor magnet 2 are attracted by this asymmetrical cogging torque generated between the tips, and are stabilized at the moved position as compared with the case where there is no notch.
[0008]
The configuration of FIG. 2 is widely used because of its simple and low cost, but it has the following disadvantages. First, since the gap length at a certain angle has a notch in the tip and undulates with rotation, a vibration component is mixed in the magnetomotive force and torque ripple increases. Second, not only electromagnetic vibration and noise are directly generated by the torque ripple, but also mechanical parts of each part of the motor are vibrated, so that an increase in noise vibration level is inevitable. Third, the notch shape increases the average gap length and increases the air gap magnetic resistance, resulting in a decrease in rotational torque, and thus a reduction in efficiency is inevitable.
[0009]
[Problems to be solved by the invention]
The first object of the present invention is a novel sensor that uses a single sensor and eliminates the need for notching a stator core, particularly in the field of a magnet motor having the same number of slots and poles, in view of the problems of the conventional magnet motor described above. Is to provide a magnet motor.
[0010]
The second problem of the present invention is to provide a novel magnet motor capable of improving the torque ripple itself, which has not been solved by the novel magnetic circuit, in addition to solving the conventional problems. It is.
[0011]
[Means for Solving the Problems]
In the present invention, a rotor magnet having a magnetic pole, position detecting means for detecting the magnetic pole position of the magnet, a soft magnetic material, and having a plurality of teeth and tips facing the magnetic pole, The stator has a wire and a drive circuit for energizing the windings. The stator provides directionality and the angle between the magnetic central axis of each tooth and the easy magnetization axis of the soft magnetic material for each tooth. By making the magnetic flux density of each tooth different, when the winding is not energized, the deviation angle in the rotation direction of the rotor magnet is obtained, the magnetic flux is linked to the position detection means, and the output of the detection means Energization of the winding is started, and a magnetic force is generated between the magnetic pole and the tip to start rotation of the rotor.
[0012]
The first feature of the present invention is that by introducing the directionality into the magnetic circuit instead of using the notch of the tap that has been used so far for the purpose of obtaining the rotation direction deviation angle of the rotor when no current is supplied. The object is to obtain the deflection angle of the rotor while using a magnetic member that is symmetrical with respect to the circumference of the rotation. In other words, the directional stator tip has no notch on the circumferential end face facing the rotor magnetic pole, and the gap length formed between the two is kept substantially constant over the entire circumference of the rotation. In addition to reducing the vibration and noise during rotation by eliminating the modulation of the magnetic force accompanying the increase / decrease of the gap length during rotation, the efficiency of the magnetic circuit is increased.
[0013]
The second feature of the present invention is that it adopts a symmetrical tip by introducing a magnetic directionality instead of the tip notch that has been used so far, and can promote the deflection angle of the rotor when energized. . That is, in a directional stator, the angle difference between the easy axis of magnetization and the central angle of each tooth is different for each tooth, and therefore the saturation magnetic flux density is different. The saturation state of each tooth changes based on the polarity, some teeth become more saturated, and some teeth are released from saturation a little, so that the deflection angle in the rotational direction of the rotor is promoted. Therefore, in the present invention, there is no angle difference between the easy magnetization axis of the stator and the tooth center angle, and even when the two coincide with each other, the spin of the rotor magnet can be obtained in the same manner as when the angle difference is provided. Can do.
[0014]
The magnetic circuit of the present invention can be applied to a synchronous motor in which the number of poles of the rotor magnet and the number of stator teeth are set to the same multiple of two. In this case, in the motor coil and the drive circuit, as in the conventional example of FIG. 2, the two energization paths shown in FIG. 3 (a) are alternately conducted, or all windings are connected to two terminals as shown in FIG. 3 (b). Or a single-phase alternating current as one energization path, or by providing two bifilar parallel windings on each tooth as shown in FIG. There is a method of exciting each tooth by energizing.
[0016]
[Action]
In a conventional magnet motor using an isotropic stator member, since the ease of magnetization is equivalent in all directions when viewed from the center angle of each tooth, if each tip is made symmetrical with respect to the tooth center angle, The attractive force generated between the tip and the magnet is generated symmetrically in the forward and reverse directions with respect to the rotation direction, and the gap portion between each tip faces the magnetized zero cross and stabilizes. Therefore, a magnetic flux does not reach the sensor located in this portion, or even if energization is obtained, no rotational torque is obtained, and a so-called start dead center is formed. For this reason, in the conventional magnetic circuit, the surface of the tape facing the magnet is cut out asymmetrically so that the attractive force is inclined asymmetrically with respect to the rotational direction. As a result, the rotor is deviated by the cogging torque and the starting dead center is eliminated, but on the other hand, vibration and noise during rotation and low efficiency are forced.
[0017]
In contrast, in the present invention, for example, a unidirectional cold-rolled silicon steel strip having magnetic characteristics shown in FIG. 4 is used as a stator material. In the figure, the horizontal axis indicates the rolling direction, that is, the angle θ [degree] from the easy magnetization axis, and the vertical axis indicates the magnetic flux density B [T]. The curve in the figure shows the relationship between the angle θ and the magnetic flux density B using various magnetic field strengths as parameters. That is, the magnetic flux density B decreases to the lower right as the angle θ increases as shown by the curves 7a to 7c when the magnetic field is weak, and slightly decreases to the lower right as shown by the curves 7d to 7e when the magnetic field is relatively strong. In any case, it can be seen that the magnetic flux concentrates on the easy axis. Therefore, even if the tip has no notch and is symmetrical, characteristics similar to the notch can be obtained by inclining the easy magnetization axis.
Further, in the shape of the stator core, the angle formed by the easy axis of the entire core and the central angle of the individual teeth differs depending on the teeth, and therefore the magnetization characteristics differ for each tooth. That is, the degree of saturation is different for each tooth, and certain teeth are less likely to be saturated, and certain teeth are more likely to be saturated. Therefore, the force that each tip exerts on the counter magnetic pole has a different value even in a non-energized state, and the axial torque as the sum of each magnetic force is modulated, so that the rotor angle can be biased.
[0018]
According to the curves 7a to 7f in FIG. 4, the magnetic flux density changes depending on the strength of the magnetic field. Therefore, the magnetic flux density of each tooth changes by energization excitation. That is, even if the stator has a bilaterally symmetric characteristic as viewed from the easy magnetization axis, it is possible to obtain an asymmetrical magnetic characteristic during energization by setting the exciting winding. In this way, it is possible to saturate a certain tooth by energization excitation and release the saturation of a certain tooth, so that the difference in the magnetic attraction force of each tip is promoted and the shaft torque as the sum of each magnetic force is changed. The rotor angle can be biased in the rotational direction.
[0019]
The basic principle of the action based on the anisotropic magnetism of the stator can be proved by an experiment in which a spherical magnet is placed on a hexahedron cut out from a soft magnetic material. That is, if the material of the hexahedron is isotropic, the sphere is stably adsorbed on any surface. However, if the hexahedron is anisotropic, the hexahedron is stably adsorbed on a surface perpendicular to the easy axis of magnetization, but is unstable on other surfaces and runs into a surface perpendicular to the easy axis of magnetization.
[0020]
【Example】
FIG. 1 shows a cross section of a magnetic circuit according to a first embodiment of the present invention. In the figure, the symbols of each part are the same as those in FIG. The magnet 1 is an isotropic Nd-bonded magnet subjected to four-pole sine wave magnetization at substantially equal intervals. The stator 2 is formed of a lamination core in which 13 unidirectional cold-rolled silicon steel strips are laminated, and the cold-rolling direction, that is, the easy axis of magnetization, is set in the direction of the arrow 2j on the drawing. In the case of the figure, the angle of the easy magnetization axis 2j is inclined 10 ° counterclockwise with respect to the central angle 2bd (line indicated by a broken line) of the teeth 2b and 2d. The shape of the outer periphery of each tip is set symmetrically with respect to the rotation direction, and the gap 4 is equal to the shortest distance between the protruding tip 2f1 and the inner periphery of the magnet 1 in the conventional example of FIG. The windings 3a, 3b, 3c, and 3d have polarities, for example, 3a and 3c are increased in magnetism, 3b and 3d are demagnetized, that is, alternately wound in different polarities, and all the windings are connected in series. The coil 3 of (b) is formed.
[0021]
When the cogging torque at the time of non-energization is calculated using the magnetic circuit of the embodiment in FIG. 1, a solid line 8a in FIG. 5 is obtained. On the other hand, the chain line 8b is obtained by changing the material to isotropic with the same stator shape and calculating the non-conductive cogging torque in the same manner. These curves almost coincide with the actually measured values. Further, when a cogging torque is measured using a symmetrical tip without a notch in a magnetic circuit using the isotropic stator of the conventional example of FIG. 2, a curve similar to 8b of FIG. 5 is obtained. Therefore, it can be seen that the cogging torque decreases when the directional stator is used.
[0022]
Here, regarding the starting dead center of the magnetic circuit in FIG. 1, when the stable points per one rotation of the rotor are obtained, there are eight as in the conventional example of FIG. 2, but the angle between adjacent dead points is 45 °. This is halved compared with the conventional example of 2. Here, if the easy magnetization axis 2j and the center angle 2bd of the teeth coincide with each other, the angle between the adjacent starting dead centers is 22.5 °, and the stable point is symmetrical with respect to the center angle of the teeth regardless of the deviation angle of the rotor. Come in position. In the illustrated case, since the easy magnetization axis 2j is inclined from the central angle 2bd, these angles are 17 ° to 28 ° with respect to the central angle 2bd, and a deviation angle in the rotational direction of the rotor is obtained.
[0023]
Considering this reason, in the conventional isotropic stator, if a symmetrical tip is used, each tooth has a symmetrical magnetic field distribution, and the zero cross of the magnet circulates and opposes the gap between the tips. There was no other way to deflect the magnetic field by providing a notch to make it asymmetrical. On the other hand, in the embodiment, a unidirectional stator is used, and the angle formed by the center angle and the easy magnetization axis varies depending on the teeth. Therefore, even when a symmetrical tip is used, individual teeth are different. As a result, the rotor can be deviated to a point that balances in axial torque.
[0024]
As described above, in the embodiment shown in FIG. 1, although the tip has no notch, the deviation angle of the rotor is obtained, the dead point is eliminated, and the sensor voltage is obtained. Therefore, when the motor coil 3 composed of the windings 3a, 3b, 3c, and 3d is connected to the drive circuit of FIG. 3B and the sensor voltage is signal-processed and applied to the semiconductor switch, the switch 6c is passed through the coil 3. -6f or the switch 6e-6d becomes conductive, and a current flows through the windings 3a-3b-3c-3d. As a result, a rotating magnetic force is generated between each magnetic pole and each tip of the magnet, and the rotor starts rotating. Thereafter, the circuit 6c-3-6f and the circuit 6e-3-6d are alternately turned on to supply the single-phase alternating current to the coil L, and the rotor continues to rotate.
[0025]
When the motor is started and the rotation speed is accelerated, when the rotation speed reaches a constant value using a load such as wind pressure in the fan or various control means, in this embodiment, the number of magnet poles and the number of teeth are reduced. Since it is the same number, it becomes a synchronous operation as shown in FIG. This figure schematically shows the magnetic force generated between the magnetic pole of the rotating magnet and each tip, and the symbols are the same as those used so far. That is, the rectangular frame shown by the solid line in FIG. 6 is developed on the paper surface when the tips 2f and 2g in FIG. 1 are viewed from the outer circumference in the direction perpendicular to the rotor axis. The dotted line frame is the same as the unfolded magnet, but the movement of the rotor magnet as it goes downward is represented by the movement of the zero cross 1a indicated by the solid line. The inequality sign displayed in the magnetic pole represents the direction of the magnetic force received from the tip facing each magnetic pole of the magnet. In addition, it may be considered that almost no force is generated in the portion where the magnet faces the gap between the tips.
According to FIG. 6, when the rotor rotates and the magnetic pole of the magnet approaches a position where it receives reverse torque, the sensor 5 detects the zero cross and reverses the energization direction and accordingly the polarity of the stator electromagnet, thereby continuing the rotation. To do. During this time, since the tip and the magnetic pole center of the magnet are synchronized, the magnetic force increases or decreases from 0 to the maximum value depending on the positional relationship between them, and harmonic vibration is generated. In such a magnetic circuit, torque in the reverse direction with respect to the rotational direction is not generated, and relatively high efficiency can be obtained. In this embodiment, the cogging torque and torque ripple can be reduced based on the directionality of the magnetic field as compared with the conventional case.
[0026]
FIG. 7 shows a cross section of the magnetic circuit of the second embodiment of the present invention. The symbols are the same as those used so far. In the figure, a rotor magnet 1 is a sine wave magnetized anisotropically oriented anisotropic rubber ferrite magnet. The number of stator tips and the number of poles are the same, but the width of the teeth 2c and 2d (the width of the portion around which the coil is wound) is set to ½ of the teeth 2a and 2b. The circumferential angle of the tips 2h and 2i (which constitutes the first tip having a relatively large angle) is 2/2 of the circumferential angle of the tips 2f and 2g (which constitutes the second tip having a relatively small angle). 3. Further, the width of the gap between the tips is not much different from the first embodiment of FIG. 1 in the interval necessary for the winding, and corresponds to 1/4 of the tips 2h and 2i. The hall sensor 5 is disposed on a non-display base plate in a gap between the tips 2c and 2d having a relatively small circumferential angle. The windings 3a, 3b, 3c, and 3d are two parallel copper wires that are alternately wound in different polarities such as increased and decreased magnetism, and motors are obtained by bifilar winding in which these windings are connected in series. Coils 31 and 32 are configured, and half-wave energization is alternately performed by the drive circuit of FIG. The number of turns of each winding is determined so that the ampere turns of the respective teeth are equal. Therefore, the number of turns of the windings 3c and 3d is ½ of the number of turns of the windings 3a and 3b.
[0027]
Here, regarding the angle difference formed by the center angle of each tooth, the angle difference between the teeth 2a and 2b is the largest, the angle difference between the teeth 2b and 2c is equal to the angle difference between 2d and 2a, and the angle between 2a and 2b. Following the difference, the angular difference between the teeth 2c and 2d is the smallest. In these teeth, 2a and 2b correspond to two teeth of a 3-slot stator, and 2c and 2d correspond to two teeth of a 6-slot stator.
In the second embodiment comprising a combination of these teeth, the cogging torque is a combination of three slots and six slots in combination with a substantially equidistant 4-pole sine wave magnetized magnet. The cogging torque based on the structure is eliminated, and as a result, the torque ripple can be greatly reduced.
[0028]
In the magnetic circuit of FIG. 7, since the sensor 5 is located between the narrow tip gaps 2h and 2i, the position of the zero cross 1a can be grasped relatively sharply. That is, the zero-cross change gradient of the output voltage is increased, and therefore, an accurate on / off signal can be transmitted to the circuit shown in FIG. 3C to facilitate the start-up and rotation of the motor. Thus, when the motor rotates, the magnetic force generated between the magnetization of the magnet 1 and each tip has the pattern shown in FIG.
In the figure, the circumferential angle of each tip and the gap between the tips is set to a ratio of 6: 1: 6: 1: 4: 1: 4: 1. In this way, since the rotational torque generated between the tip and the magnet pole is all in the forward direction as shown by the inequality sign in the figure, the torque component in the reverse direction can be eliminated. Therefore, the motor efficiency can be increased, or a magnet material having a low maximum magnetic flux density can be used. In this case, since all the magnetic poles and all the tips are avoided from being synchronized, the vibration frequency can be distributed. Such an effect can also be obtained in various combinations such as a multi-slot configuration obtained by multiplying the magnetic circuit of FIG. 7 by an integer, or by changing the ratio of the teeth width 1/2 to 2/3. And torque ripple can be reduced.
[0029]
In the second embodiment of the present invention, an isotropic material or a non-radially oriented anisotropic magnet can be used instead of the radially oriented anisotropic magnet. In the former case, magnetization asymmetric with respect to the rotation direction is used, and in the latter case, for example, the orientation direction and magnetization direction of the material are inclined by about 30 ° from the radial direction. In such a motor, since the directionality of the stator and the magnet anisotropy are synergistic, the deflection angle of the rotor can be increased. Such a second embodiment can also be applied to a conventional isotropic stator core.
[0030]
The configuration of the second embodiment of the present invention is based on the setting of a special stator shape that can specify the partial torque that acts between the stator tip and the magnet pole. It is not limited to the lamination core shown in FIG. 7, but also for a magnetic circuit that applies a magnetic force acting on the surface of a single-plate stator tip formed by a punched steel plate, such as an inductor motor, for example. It can be similarly applied by adopting a plurality of tip shapes.
[0031]
The two embodiments of the present invention in which anisotropy is imparted to the magnetic circuit having the 4-slot and 4-pole configuration have been described above. However, the application range of the present invention is not limited to the configurations of the first and second embodiments. The present invention can be widely applied to various motors using a magnetic field and driving without departing from the technical basis. For example, a stator with both directionality and isotropicity, a multi-directional stator such as bi-directional, a magnetic circuit with an increased number of poles and slots, a magnet with multiple orientation directions, and an inner rotor type magnetism Circuits other than Hall sensors or sensorless type magnetic detection means, various coil connections including parallel connection, and the method of applying the present invention only to startup and driving in multiple phases during rotation can be selectively used. .
[0032]
【The invention's effect】
According to the present invention, by introducing an anisotropic magnetic field to a magnet motor, a degree of freedom is given to change of the shape of the stator or the material of the magnet, and as a result, it becomes possible to create an unprecedented characteristic function. It was. That is, according to the present invention, it is not necessary to apply special mechanical deformation to the magnetic circuit for eliminating the start dead center, and the pure electromagnetic method reduces the cogging torque to reduce vibration and noise, and is high. It became possible to obtain efficiency.
[0033]
In the first embodiment, by introducing anisotropy into the magnetic circuit of the motor, the starting dead center is eliminated, and the notch of the stator tip, which has been essential so far, is eliminated to reduce vibration and noise. It was possible to reduce. It was also possible to reduce the cogging torque and thus reduce the torque ripple. Furthermore, the average gap length was reduced and the motor efficiency could be increased.
[Brief description of the drawings]
FIG. 1 shows a cross section of a magnetic circuit of a first embodiment of a magnet motor according to the present invention.
FIG. 2 shows a cross section of a magnetic circuit of a conventional fan motor.
FIG. 3 shows power stages of various single-phase excitation drive circuits.
FIG. 4 shows the nature of the non-energized cogging torque of the first embodiment.
FIG. 5 shows a relationship between angle and magnetic flux density of a directional silicon electromagnetic steel strip.
FIG. 6 shows the nature of partial torque generated at each tip of the first embodiment.
FIG. 7 shows a cross section of a magnetic circuit of a second embodiment of the magnet motor according to the present invention.
FIG. 8 shows the nature of partial torque generated in each tip of the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor magnet 2 Stator 2a Stator tooth 2b Stator tip 2j Stator easy magnetization shaft 3 Coil 4 Air gap 5 Magnetic sensor 6a Semiconductor switch

Claims (3)

A rotor magnet provided with magnetic poles, a position detection means for detecting the magnetic pole position of the magnet, a soft magnetic material, having a plurality of teeth and tips facing the magnetic poles, and an excitation winding in the teeth. In a magnet motor having a stator and a drive circuit for energizing the windings,
The stator is configured by laminating a plurality of lamination cores obtained by punching a soft magnetic material having a unidirectional easy magnetization axis without dividing a plurality of teeth, and the stator tip faces the rotor magnet. no cutout portion in the circumferential end surface, with the gap length to be formed between the inner peripheral surface of the magnet is kept substantially constant over the rotation direction the entire circumference, before Symbol central axis soft of each tooth The angle formed by the easy magnetization axis of the magnetic material is made different for each tooth, and when the winding is not energized, the magnetic flux supplied from the magnet to the tip is deflected to deviate the rotor magnet in the rotation direction. Accordingly, the position detecting means in energized open Hajimesu Rutotomoni of obtaining the linkage field to said winding with a its detection output, and the pole the Te Magnet motor, characterized in that allowed to start the rotation of the rotor by a magnetic force generated between the class tap. A rotor magnet provided with magnetic poles, a position detection means for detecting the magnetic pole position of the magnet, a soft magnetic material, having a plurality of teeth and tips facing the magnetic poles, and an excitation winding in the teeth. In a magnet motor having a stator and a drive circuit for energizing the windings,
The stator is formed by laminating a plurality of lamination cores obtained by punching a soft magnetic material having a unidirectional easy magnetization axis without dividing a plurality of teeth, and the stator tip faces the rotor magnet. no cutout portion in the circumferential end surface for, with the gap length to be formed between the inner peripheral surface of the magnet is kept substantially constant over the rotation direction the entire circumference, and the center axis of the front Symbol the teeth The angle formed by the easy magnetization axis of the soft magnetic material is made different for each tooth, the magnetic flux density of each tooth is made different, and the difference in the magnetic flux density is promoted by energization of the winding, thereby rotating the rotor magnet. Increasing the deflection angle of the direction to increase the flux linkage to the position detection means, switching the energization to the winding with the detection output, Magnet motor, characterized in that which can be rotated the rotor by a magnetic force generated between the To pole tip.   The number of poles of the magnet and the total number of teeth are set to a multiple of 2 and the same number, and the polarity of adjacent teeth is alternated with respect to each of the teeth sequentially arranged in the circumferential direction. 3. The magnet motor according to claim 1, wherein the magnet motors are wound so as to have different polarities, are energized by the drive circuit, and excite the teeth alternately or all at the same time.

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